Title of article :
Synthesis and structure of environmentally relevant perfluorinated sulfonamides
Author/Authors :
Lehmler، نويسنده , , Hans-Joachim and Rama Rao، نويسنده , , V.V.V.N.S. and Nauduri، نويسنده , , Dhananjaya and Vargo، نويسنده , , John D. and Parkin، نويسنده , , Sean، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2007
Abstract :
Alkylated perfluorooctanesulfonamides are compounds of environmental concern. To make these compounds available for environmental and toxicological studies, a series of N-alkylated perfluorooctanesulfonamides and structurally related compounds were synthesized by reaction of the corresponding perfluoroalkanesulfonyl fluoride with a suitable primary or secondary amine. Perfluoroalkanesulfonamidoethanols were obtained from the N-alkyl perfluoroalkanesulfonamides either by direct alkylation with bromoethanol or alkylation with acetic acid 2-bromo-ethyl ester followed by hydrolysis of the acetate. N-Alkyl perfluorooctanesulfonamidoacetates were synthesized in an analogous way by alkylation of N-alkyl perfluoroalkanesulfonamides with a bromo acetic acid ester, followed by basic ester hydrolysis. Alternatively, N-alkyl perfluoroalkanesulfonamides can be alkylated with an appropriate alcohol using the Mitsunobu reaction. Perfluorooctanesulfonamide was synthesized from the perfluorooctanesulfonyl fluoride via the azide by reduction with Zn/HCl. All perfluorooctanesulfonamides contained linear as well as branched C8F17 isomers, typically in a 10:1 to 30:1 ratio. The crystal structures of N-ethyl and N,N-diethyl perfluorooctanesulfonamide show that the S–N bond has considerable double bond character. This double bond character results in a significant rotational barrier around the S–N bond (ΔG≠ = 62–71 kJ mol−1) and a preferred solid state and solution conformation in which the N-alkyl groups are oriented opposite to the perfluorooctyl group to minimize steric crowding around the S–N bond.
Keywords :
Environmental contaminants , Perfluorooctanesulfonamides , Perfluorobutanesulfonamides , Mitsunobu reaction , X-ray structure , Alkylation
Journal title :
Journal of Fluorine Chemistry
Journal title :
Journal of Fluorine Chemistry